We use a simplified model of interconnected synchronous machines,
derived from the dynamics of the rotor to model a power grid. The
classic constant-voltage behind the transient-reactance model
then gives
the swing equations (see e.g., [1]}, [2]}) which are
derived from energy conservation. The Kuramoto-like model used in
[3]}, [4]}, [2]} is directly related to
this swing equation. On each node \(i\)  of the network either a
synchronous generator or a synchronous motor are placed. The generators
exhibit power plants and therefore produce power
(\(P_i^{\rm source} > 0\) ), whereas the motors consume power
(\(P_i^{\rm source} < 0\) ).
